1. Field of the Invention
The present invention relates to an electromagnetic relay.
2. Description of Relevant Art
An example of a conventional electromagnetic relay is shown in FIG. 9.
In the electromagnetic relay of FIG. 9, a coil block 5 is accommodated in a housing part 2 of a box-like base 1. A terminal 4 exposed from an upper surface of the base 1 is welded to a terminal 8 protruding at a hook part 7 formed at each end of a spool 6 of the coil block 5. A movable block 12 is attached to a permanent magnet 9 mounted at the center of the coil block 5 in a swaying fashion. A casing 17 is fitted into the base 1 after all the components of the electromagnetic relay are arranged as above.
The electromagnetic relay in the aforementioned structure operates in the following manner. That is, when a voltage is impressed to a coil 10 of the coil block 5, the opposite ends of a movable iron element 13 of the movable block 12 are alternately attracted to the ends of a yoke 11 confronting thereto. As a consequence, a movable contact 15 at each end of a movable contact piece 14 which is supported by a supporting part 16 at either side of the movable iron element 13 is brought into contact with or detached from a fixed contact 3 exposed at an upper surface of the side wall of the base 1.
According to the above-described structure of the electromagnetic relay, it is difficult to keep a sufficient distance between each of the contacts 3, 15 and the coil 10 as it is a recent trend to make the relay compact in size. Therefore, the dielectric strength therebetween has been undesirably lowered.
As a solution to the above problem, the coil part has been coated in some cases with an insulative resin after the coil block 5 was assembled. However, this method takes a deal of cost and labor.